This invention relates to machines for refinishing the side surfaces of air seal flanges of turbine blades which have become worn and otherwise no longer useful. Heretofore, many turbine blades after having served an initial useful life, were discarded since they were considered as not recoverable or repairable. This represented a considerable expense, and was a wasteful process since the blades were cast of special alloy metal, and required complicated molds and costly finishing operations whereby their fabrication represented a high cost.
According to the present invention, blades having worn air seal flanges can be effectively repaired whereby their useful life is greatly extended, thus resulting in a considerable saving of money and time. The worn air seal flanges of the blades are builtup by adding metal, as with an electro-welding process, and thereafter the blades are placed in an apparatus which refinishes the built-up seal flanges at both side surfaces. This is accomplished by a machine comprising a bench or table having a flat top surface on which one or several pressure shoes are pivotally mounted at a work-performing station. One or several cutting belts having surfaces provided with cutting particles are mounted on pulleys so that the cutting surfaces pass (in the case of two belts) between two pressure shoes, in face-to-face, spaced relation to each other with the backs of the belts facing the shoes. The shoes are provided with handles by which they can be pivotally actuated to advance them against the backs of the belts so as to make the cutting surfaces of the belts approach each other. On the top of the bench a slide is provided, having clamping means adapted to accommodate a turbine blade in such a manner that the air seal flange thereof can be interposed between the spaced apart cutting belts at the work-performing station. Thereafter, when the pressure shoes are actuated to force the cutting surfaces of the belts against the opposite sides of the air seal flange, the excess metal is removed therefrom. Adjustable stop means are provided on the bench top, engageable with the pressure shoes to limit the pivoting movement thereof to that required for removing only the desired amount of excess metal. A guide adjustably secured to the bench top facilitates the correct positioning of the turbine blade so that the seal flange thereof can be readily interposed between the cutting surfaces of the belts.
A safety feature of the invention resides in the provision of the two handles, requiring the operator to use both hands in order to carry out the refinishing operation whereby there is minimized the likelihood of injury from contact with the cutting belts.
Each cutting belt is individually driven by its own motor, and passes over its own system of pulleys, thereby effecting a desirable simplicity of the machine and minimizing maintainance and servicing.